Browsing by Subject "CO2"
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Item Case Study – Solar Panel Installation in Mitsubishi Turbocharger and Engine America Plant – Feasibility Study(2022-08-02) Bajgoric, Kenan; Ray, Veto; Koo, Dan; Dalir, HamidData collected from the MTEA site as well as contractor-provided information was analyzed and reviewed to show how solar power can contribute to MTEA's overarching strategic plan of reducing CO2 emissions and lowering operating costs. This study is significant because the results will demonstrate that harnessing solar energy is financially and technologically feasible for MTEA.Item Data-driven Demand Control Ventilation Using Machine Learning CO2 Occupancy Detection Method(2020-07) Momeni, Mehdi; Wu, Da-Chun; Razban, Ali; Chen, Jie; Mechanical and Energy Engineering, School of Engineering and TechnologyHeating, ventilation, and air-conditioning (HVAC) system accounts for approximately 40% of total building energy consumption in the United States. Currently, most buildings still utilize constant air volume (CAV) systems with on/off control to meet the thermal loads. Such systems, without any consideration of occupancy, may ventilate a room excessively and result in a waste of energy. Previous studies show that CO2-based demand-controlled ventilation methods are the most widely used strategies to determine the optimal level of supply air volume. However, conventional CO2 mass balanced models do not yield an optimal estimation accuracy. In this manuscript, a data-driven control strategy was developed to optimize the energy consumption of supply fans by feed-forward neural network to predict real-time occupancy as an active constraint. As for the validation, the experiment was carried out in an auditorium located on a university campus. The result shows, after utilizing feed-forward neural network to enhance the occupancy estimation, the new primary fan schedule can reduce the daily ventilation energy by 75% when compared to the current on/off control.Item Demand Controlled Ventilation Energy Savings for Air Handling Units(2021-12) Blubaugh, Matthew; Chen, Jie; Razban, Ali; Goodman, DavidHeat, cooling, and ventilation units are major energy consumers for commercial buildings, they can consume as much as 50% of the total annual power usage of a building. Coherent management of an air handling system’s energy is a key factor of reducing the energy costs and CO2 emissions that are associated with the demand for ventilating and conditioning the air in a building. The issue is that buildings are frequently over ventilated as a full assessment of the air handling unit (AHU) data is not evaluated by building operators. According to ASHRAE standards there are three key parameters that control indoor air quality (IAQ); these are the temperature, humidity, and CO2. Commonly occupancy setpoints implemented by building operators are focused on temperature and humidity control while neglecting the CO2 levels and their impact. While this may seem insignificant additional data proves to be important and can assist with energy management. Additionally, it can develop awareness of implementable procedures which conserve energy. Furthermore, data is not monitored in regard to the continuous assessment of the energy consumption with respect to analysis of opportunities to implement energy saving control strategies. By using these standards as a guide an AHUs energy can be managed more effectively by measuring the data and assessing the outputs compared to the standard. Previous research has shown that up to 75% savings for the ventilation fan energy is achievable when taking into account ASHRAE ventilation standards and controlling outside air ventilation, however, this research has omitted investigating the savings for other energy consumers associated with AHU’s operation. In order to assess the demand, it is required that the CO2 levels of the occupied zones be measured, and the outdoor air ventilation rate be adjusted based on real-time demand. The goal of the research is to assess the number of CO¬2 sensors needed to accurately measure demand-based needs for ventilation and determine an algorithm that will help building operators assess the energy savings by implementing demand-controlled ventilation (DCV) procedures. The scope of this research is to identify what sensors at minimum are required to collect the most pertinent data for implementation of a comprehensive energy saving algorithms and assess the impact on energy consumption of AHUs when demand-controlled ventilation procedures are implemented.Item Equivalence of arterial and venous blood for [11C]CO2-metabolite analysis following intravenous administration of 1-[11C]acetate and 1-[11C]palmitate(Elsevier, 2013-04) Ng, Yen; Moberly, Steven P.; Mather, Kieren J.; Brown-Proctor, Clive; Hutchins, Gary D.; Green, Mark A.; Department of Cellular & Integrative Physiology, IU School of MedicinePURPOSE: Sampling of arterial blood for metabolite correction is often required to define a true radiotracer input function in quantitative modeling of PET data. However, arterial puncture for blood sampling is often undesirable. To establish whether venous blood could substitute for arterial blood in metabolite analysis for quantitative PET studies with 1-[(11)C]acetate and 1-[(11)C]palmitate, we compared the results of [(11)C]CO2-metabolite analyses performed on simultaneously collected arterial and venous blood samples. METHODS: Paired arterial and venous blood samples were drawn from anesthetized pigs at 1, 3, 6, 8, 10, 15, 20, 25 and 30min after i.v. administration of 1-[(11)C]acetate and 1-[(11)C]palmitate. Blood radioactivity present as [(11)C]CO2 was determined employing a validated 10-min gas-purge method. Briefly, total blood (11)C radioactivity was counted in base-treated [(11)C]-blood samples, and non-[(11)C]CO2 radioactivity was counted after the [(11)C]-blood was acidified using 6N HCl and bubbled with air for 10min to quantitatively remove [(11)C]CO2. RESULTS: An excellent correlation was found between concurrent arterial and venous [(11)C]CO2 levels. For the [(11)C]acetate study, the regression equation derived to estimate the venous [(11)C]CO2 from the arterial values was: y=0.994x+0.004 (r(2)=0.97), and for the [(11)C]palmitate: y=0.964x-0.001 (r(2)=0.9). Over the 1-30min period, the fraction of total blood (11)C present as [(11)C]CO2 rose from 4% to 64% for acetate, and 0% to 24% for palmitate. The rate of [(11)C]CO2 appearance in venous blood appears similar for the pig model and humans following i.v. [(11)C]-acetate administration. CONCLUSION: Venous blood [(11)C]CO2 values appear suitable as substitutes for arterial blood samples in [(11)C]CO2 metabolite analysis after administration of [(11)C]acetate or [(11)C]palmitate ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: Quantitative PET studies employing 1-[(11)C]acetate and 1-[(11)C]palmitate can employ venous blood samples for metabolite correction of an image-derived tracer arterial input function, thereby avoiding the risks of direct arterial blood sampling.Item Etiology, triggers and neurochemical circuits associated with unexpected, expected, and laboratory-induced panic attacks(Elsevier, 2014-10) Johnson, Philip L.; Federici, Lauren M.; Shekhar, Anantha; Department of Psychiatry, IU School of MedicinePanic disorder (PD) is a severe anxiety disorder that is characterized by recurrent panic attacks (PA), which can be unexpected (uPA, i.e., no clear identifiable trigger) or expected (ePA). Panic typically involves an abrupt feeling of catastrophic fear or distress accompanied by physiological symptoms such as palpitations, racing heart, thermal sensations, and sweating. Recurrent uPA and ePA can also lead to agoraphobia, where subjects with PD avoid situations that were associated with PA. Here we will review recent developments in our understanding of PD, which includes discussions on: symptoms and signs associated with uPA and ePAs; Diagnosis of PD and the new DSM-V; biological etiology such as heritability and gene×environment and gene×hormonal development interactions; comparisons between laboratory and naturally occurring uPAs and ePAs; neurochemical systems that are associated with clinical PAs (e.g. gene associations; targets for triggering or treating PAs), adaptive fear and panic response concepts in the context of new NIH RDoc approach; and finally strengths and weaknesses of translational animal models of adaptive and pathological panic states.Item Evaluation of Low versus High Volume per Minute Displacement CO₂ Methods of Euthanasia in the Induction and Duration of Panic-Associated Behavior and Physiology(MDPI, 2016-08) Hickman, Debra L.; Fitz, Stephanie D.; Bernabe, Cristian S.; Caliman, Izabela F.; Haulcomb, Melissa M.; Federici, Lauren M.; Shekhar, Anatatha; Johnson, Philip L.; Department of Cellular & Integrative Physiology, IU School of MedicineCurrent recommendations for the use of CO ₂ as a euthanasia agent for rats require the use of gradual fill protocols (such as 10% to 30% volume displacement per minute) in order to render the animal insensible prior to exposure to levels of CO ₂ that are associated with pain. However, exposing rats to CO ₂ , concentrations as low as 7% CO ₂ are reported to cause distress and 10%-20% CO ₂ induces panic-associated behavior and physiology, but loss of consciousness does not occur until CO ₂ concentrations are at least 40%. This suggests that the use of the currently recommended low flow volume per minute displacement rates create a situation where rats are exposed to concentrations of CO ₂ that induce anxiety, panic, and distress for prolonged periods of time. This study first characterized the response of male rats exposed to normoxic 20% CO ₂ for a prolonged period of time as compared to room air controls. It demonstrated that rats exposed to this experimental condition displayed clinical signs consistent with significantly increased panic-associated behavior and physiology during CO ₂ exposure. When atmospheric air was then again delivered, there was a robust increase in respiration rate that coincided with rats moving to the air intake. The rats exposed to CO ₂ also displayed behaviors consistent with increased anxiety in the behavioral testing that followed the exposure. Next, this study assessed the behavioral and physiologic responses of rats that were euthanized with 100% CO ₂ infused at 10%, 30%, or 100% volume per minute displacement rates. Analysis of the concentrations of CO ₂ and oxygen in the euthanasia chamber and the behavioral responses of the rats suggest that the use of the very low flow volume per minute displacement rate (10%) may prolong the duration of panicogenic ranges of ambient CO ₂ , while the use of the higher flow volume per minute displacement rate (100%) increases agitation. Therefore, of the volume displacement per minute rates evaluated, this study suggests that 30% minimizes the potential pain and distress experienced by the animal.Item Home Cage Compared with Induction Chamber for Euthanasia of Laboratory Rats(American Association for Laboratory Animal Science, 2018-10-10) Hickman, Debra L.; Laboratory Animal Resource Center, IU School of MedicineThis study compared behavioral and physiologic changes in Sprague-Dawley and Brown Norway rats that were euthanizedby using a 30% volume displacement rate of CO2 in either their home cage or an induction chamber; rats euthanized in thehome cage were hypothesized to demonstrate a higher level of animal wellbeing. No significant differences were detectedin the physiologic responses to home cage versus induction chamber euthanasia groups. A few strain-related behavioraldifferences occurred. The number of digs per second was higher in Brown Norway compared with Sprague-Dawley rats when in the home cage, where a digging substrate was present. Rearing frequency was higher in both Brown Norway and Sprague-Dawley rats in the induction chamber compared with the home cage. This study demonstrated that although strainspecific differences were associated with the process of euthanasia, there were no significant differences between the treatment groups of home cage compared with induction chamber. This finding suggests that-from the perspective of a rat-either the home cage or an induction chamber can be used for euthanasia, with likely extension of this conclusion to use of either method to the induction of anesthesia.Item Increased Global Vegetation Productivity Despite Rising Atmospheric Dryness Over the Last Two Decades(AGU, 2022-07) Song, Yang; Jiao, Wenzhe; Wang, Jing; Wang, Lixin; Earth and Environmental Sciences, School of ScienceRising atmospheric dryness [vapor pressure deficit (VPD)] can limit photosynthesis and thus reduce vegetation productivity. Meanwhile, plants can benefit from global warming and the fertilization effect of carbon dioxide (CO2). There are growing interests to study climate change impacts on terrestrial vegetation. However, global vegetation productivity responses to recent climate and CO2 trends remain to be fully understood. Here, we provide a comprehensive evaluation of the relative impacts of VPD, temperature, and atmospheric CO2 concentration on global vegetation productivity over the last two decades using a robust ensemble of solar-induced chlorophyll fluorescence (SIF) and gross primary productivity (GPP) data. We document a significant increase in global vegetation productivity with rising VPD, temperature, and atmospheric CO2 concentration over this period. For global SIF (or GPP), the decrease due to rising VPD was comparable to the increase due to warming but far less than the increase due to elevated CO2 concentration. We found that rising VPD counteracted only a small proportion (approximately 8.1%–15.0%) of the warming and CO2-induced increase in global SIF (or GPP). Despite the sharp rise in atmospheric dryness imposing a negative impact on plants, the warming and CO2 fertilization effects contributed to a persistent and widespread increase in vegetation productivity over the majority (approximately 66.5%–72.2%) of the globally vegetated areas. Overall, our findings provide a quantitative and comprehensive attribution of rising atmospheric dryness on global vegetation productivity under concurrent climate warming and CO2 increasing.Item Water and nitrogen availability co-control ecosystem CO2 exchange in a semiarid temperate steppe(Springer Nature, 2015-10-23) Zhang, Xiaolin; Tan, Yulian; Li, Ang; Ren, Tingting; Chen, Shiping; Wang, Lixin; Huang, Jianhui; Department of Earth Sciences, School of ScienceBoth water and nitrogen (N) availability have significant effects on ecosystem CO2 exchange (ECE), which includes net ecosystem productivity (NEP), ecosystem respiration (ER) and gross ecosystem photosynthesis (GEP). How water and N availability influence ECE in arid and semiarid grasslands is still uncertain. A manipulative experiment with additions of rainfall, snow and N was conducted to test their effects on ECE in a semiarid temperate steppe of northern China for three consecutive years with contrasting natural precipitation. ECE increased with annual precipitation but approached peak values at different precipitation amount. Water addition, especially summer water addition, had significantly positive effects on ECE in years when the natural precipitation was normal or below normal, but showed trivial effect on GEP when the natural precipitation was above normal as effects on ER and NEP offset one another. Nitrogen addition exerted non-significant or negative effects on ECE when precipitation was low but switched to a positive effect when precipitation was high, indicating N effect triggered by water availability. Our results indicate that both water and N availability control ECE and the effects of future precipitation changes and increasing N deposition will depend on how they can change collaboratively in this semiarid steppe ecosystem.